Question

How many protons, electrons and neutrons are present in $0.18$ $g$ ${}_{15}^{30}P$?

Answer 1

Number of protons in one atom of $P=$ Number of electrons in one atom of $P=15$
Number of neutrons in one atom of $P=(A-Z)$
$=(30-15)=15$
$0.18$ $g$ ${}_{15}^{30}P=\frac{0.18}{30}=0.006$ $mol$
Number of atoms in $0.006$ $mol=0.006\times 6.02\times {10}^{23}$
Number of protons in $0.006$ $mol$ ${}_{15}^{30}P=15\times 0.006\times 6.02\times {10}^{23}=5.418\times {10}^{22}$
So, Number of electrons $=5.418\times {10}^{22}$
and Number of neutrons $=5.418\times {10}^{22}$.